/**
 * 由一个组件，向上找到最近的指定组件
 * @param context 当前上下文 this
 * @param componentName 组件的name
 * @returns {Vue}
 */
const findComponentUpward = (context, componentName) => {
  let parent = context.$parent;
  let name = parent.$options.name;

  while (parent && (!name || [componentName].indexOf(name) < 0)) {
    parent = parent.$parent;
    if (parent) name = parent.$options.name;
  }
  return parent;
};

/**
 * 由一个组件，向上找到所有的指定组件
 * @param context 当前上下文 this
 * @param componentName 组件的name
 * @returns {*}
 */
const findComponentsUpward = (context, componentName) => {
  const parents = [];
  const parent = context.$parent;

  if (parent) {
    if (parent.$options.name === componentName) parents.push(parent);
    return parents.concat(findComponentsUpward(parent, componentName));
  } else {
    return [];
  }
};

/**
 * 由一个组件，向下找到最近的指定组件
 * @param context 当前上下文 this
 * @param componentName 组件的name
 * @returns {*}
 */
const findComponentDownward = (context, componentName) => {
  const childrens = context.$children;
  let children = null;

  if (childrens.length) {
    for (const child of childrens) {
      const name = child.$options.name;

      if (name === componentName) {
        children = child;
        break;
      } else {
        children = findComponentDownward(child, componentName);
        if (children) break;
      }
    }
  }
  return children;
};

/**
 * 由一个组件，向下找到所有指定的组件
 * @param context 当前上下文 this
 * @param componentName 组件的name
 * @returns {*}
 */
const findComponentsDownward = (context, componentName) => {
  return context.$children.reduce((components, child) => {
    if (child.$options.name === componentName) components.push(child);
    const foundChilds = findComponentsDownward(child, componentName);
    return components.concat(foundChilds);
  }, []);
};

/**
 * 由一个组件，找到指定组件的兄弟组件
 * @param context 当前上下文 this
 * @param componentName 组件的name
 * @param exceptMe 是否把本身除外
 * @returns {*}
 */
const findBrothersComponents = (context, componentName, exceptMe = true) => {
  const res = context.$parent.$children.filter(item => {
    return item.$options.name === componentName;
  });
  const index = res.findIndex(item => item._uid === context._uid);
  if (exceptMe) res.splice(index, 1);
  return res;
};

export {
  findComponentUpward,
  findComponentsUpward,
  findComponentDownward,
  findComponentsDownward,
  findBrothersComponents,
};
